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Diadème (satellites)
Diadème is the name of a pair of French artificial satellites of the D-1 series developed by CNES and built by Matra, launched in February 1967 using Diamant rockets. Like the first satellite of the Diapason series (D-1A), the purpose of Diadème 1 and 2 was to carry out geodetic surveys using Doppler and laser telemetry techniques. They were also used to test a satellite navigation system. Characteristics Both satellites had a mass of about 23 kg. In addition to the Doppler oscillator and laser reflectors, the satellites also carried a radio beacon operating at 136 MHz for the transmission of telemetry data. It was also equipped with a "solar cell" experiment, where the battery was recharged by a solar generator. The satellites were stabilized relative to the Earth's magnetic field, with the satellite's axis tangent to the lines of force. Initially only three French tracking stations, all around the Mediterranean, tracked the satellites. Later a worldwide tracking programme w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CNES
CNES () is the French national space agency. Headquartered in central Paris, the agency is overseen by the ministries of the Armed Forces, Economy and Finance and Higher Education, Research and Innovation. It operates from the Toulouse Space Centre and the Guiana Space Centre. The president of CNES is Philippe Baptiste. CNES is a member of Institute of Space, its Applications and Technologies. It is Europe's largest national organization of its type. History CNES was established under President Charles de Gaulle in 1961. It is the world's third oldest space agency, after the Soviet space program (Russia), and NASA (United States). CNES was responsible for the training of French astronauts, until the last active CNES astronauts transferred to the European Space Agency in 2001. , CNES is working with Germany and a few other governments to start a modest research effort with the hope to propose a LOX/methane reusable launch vehicle by mid-2015. If built, flight testing w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matra
Matra (an acronym for Mécanique Aviation Traction) was a major French industrial Conglomerate (company), conglomerate. Its business activities covered a wide range of industries, notably aerospace manufacturer, aerospace, defence industry, defence, automotive industry, automotive, motorsports, transport and telecommunications. Following the acquisition of vehicle manufacturer Automobiles René Bonnet, the company founded Matra Automobiles during the 1960s, which produced a limited range of racing and sports cars. Its car division worked closely with other vehicle manufacturers, most significantly Renault, prior to the decline and sale of Matra Automobiles during the early 2000s. In addition to road cars, Matra entered into a wide range of businesses, eventually diversifying into Media (communication), media, weaponry, aeronautics, automobiles, and music distribution. Matra was at one point owned by the Floirat family. Throughout much of the company's existence, French business ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamant
The Diamant rocket (French for "diamond") was the first exclusively French expendable launch system and at the same time the first satellite launcher not built by either the United States or USSR. As such, it has been referred to as being a key predecessor for all subsequent European launcher projects. The head of the project, Charley Attali, received the Legion of Honour in 1965 for the Diamant. During 1962, development of the Diamant commenced as the inaugural spacecraft project of France's space agency, the CNES, Centre National d'Études Spatiales (CNES). As a project, it was derived from the military program ''pierres précieuses'' (fr.: gemstones) that included the five prototypes Agate (rocket), Agate, Topaze (rocket), Topaze, Emeraude (rocket), Emeraude, Rubis (rocket), Rubis and Saphir (rocket), Saphir (Agate, Topaz, Emerald, Ruby and Sapphire), and drew heavily upon the knowledge and technologies that had been previously developed. On 26 November 1965, the Diamant A pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The ''Doppler effect'' is named after the physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. When the source of the sound wave is moving towards the observer, each successive cycle of the wave is emitted from a position closer to the observer than the previous cycle. Hence, from the observer's perspective, the time between cycles is reduced, meaning the frequency is increased. Conversely, if the source of the sound wave is moving away from the observer, each cycle of the wave is emitted from a position farther from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Navigation
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). , four global systems are operational: the United States's Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), China's BeiDou Navigation Satellite System (BDS), and the European Union, European Union's Galileo (satellite navigation), Galileo. Two regional systems are operational: India's Indian Regional Navigation Satellite System, NavIC and Japan's Quasi-Zenith Satellite System, QZSS. ''Satellite-based augmentation systems'' (SBAS), designed to enhance the accuracy of GNSS, include Japan's Quasi-Zenith Satellite System (QZSS), India's GAGAN and the European EGNOS, all of them based on GPS. Previous iterations of the BeiDou navigation system and the present Indian Regional Navigation Satellite System (IRNSS), operationally known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Reflector Array
A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects light or other radiation back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence. Being directed, the retroflector's reflection is brighter than that of a diffuse reflector. Corner reflectors and cat's eye reflectors are the most used kinds. Types There are several ways to obtain retroreflection: Corner reflector A set of three mutually perpendicular reflective surfaces, placed to form the internal corner of a cube, work as a retroreflector. The three corresponding normal vectors of the corner's sides form a basis in which to represent the direction of an arbitrary incoming ray, . When the ray reflects from the first side, say x, the ray's ''x''-component, ''a'', is reversed to −''a'', while the ''y'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Beacon
In navigation, a radio beacon or radiobeacon is a kind of beacon, a device that marks a fixed location and allows direction finding, direction-finding equipment to find relative Bearing (navigation), bearing. But instead of employing visible light, radio beacons transmit electromagnetic radiation in the radio wave electromagnetic spectrum, band. They are used for direction-finding systems on ships, aircraft and vehicles. Radio beacons transmitter, transmit a continuous or periodic radio signal with limited information (for example, its identification or location) on a specified radio frequency. Occasionally, the beacon's transmission includes other information, such as telemetry, telemetric or meteorological data. Radio beacons have many applications, including air and sea navigation, propagation research, robotic mapping, radio-frequency identification (RFID), near-field communication (NFC) and indoor navigation, as with real-time locating systems (RTLS) like Syledis or simulta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cell
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.Solar Cells chemistryexplained.com It is a type of photoelectric cell, a device whose electrical characteristics (such as Electric current, current, voltage, or Electrical resistance and conductance, resistance) vary when it is exposed to light. Individual solar cell devices are often the electrical building blocks of solar panel, photovoltaic modules, known colloquially as "solar panels". Almost all commercial PV cells consist of crystalline silicon, with a market share of 95%. Cadmium telluride thin-film solar cells account for the remainder. The common single-junction silicon solar cell can produce a maximum open-circuit voltage o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Magnetic Field
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from structure of Earth, Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of Earth's magnetic field at its surface ranges from . As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth. The North geomagnetic pole (Ellesmere Island, Nunavut, Canada) actually represents the South pole of Earth's magnetic field, and conversely the South geomagnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centre Interarmées D'essais D'engins Spéciaux
The Centre Interarmées d'Essais d'Engins Spéciaux (CIEES, ) was France's first space launch and ballistic missile testing facility. Outside France, the facility is often referred to by the name of the nearest town, Hammaguir. It was established on 24 April 1947, by ministerial decree as the Special Weapons Test Center (CEES, ''Centre d'essais d'engins spéciaux'') for use by the French Army. In 1948, it was turned over to the French Air Force, who renamed it CIEES. Its remote location in the middle of the Saharan Desert and its relative closeness to the Equator (compared with Metropolitan France) made it an attractive launch site for missiles and orbital rockets. History The origins of CIEES and the French missile and space program date to the end of the Second World War. On 12 June 1945, less than a month after V-E Day, the War Department ordered the study of self-propelled projectiles (rockets). On 13 August, the Directorate of Studies and Manufactures of Armaments (DEFA) p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
